Hi.
run this command:
root@OpenWrt:~# echo AT+CGDCONT? | socat - /dev/ttyUSB1,crnl
in my case, it will report this:
AT+CGDCONT?
+CGDCONT: 1,"IP","internet","0.0.0.0",0,0,0,0,0,0
"internet" is my isp apn, it was defined by running this command:
echo at+qicsgp=1,1,"internet" | socat - /dev/ttyUSB1,crnl